1. Field of the Invention
The present disclosure is generally related to a control assembly for power steering.
2. Related Art
This section provides background information related to the present disclosure which is not necessarily prior art.
Power steering or assist steering systems are implemented for reducing the amount of human effort required to turn the steering wheel of an automobile. Traditionally, these systems utilize hydraulic lines to add supplementary steering force to a steering gear by way of hydraulic fluid via a hydraulic pressure cylinder. This supplementary steering force is typically turned off and on by a control assembly that includes a shaft disposed within and rotatable relative to a valve sleeve. In these systems, the shaft extends between a torsion bar and a steering gear and conveys rotational movement between the steering wheel and a steering gear. In operation the shaft must be slightly rotated before the control assembly allows the supplementary steering force to be applied. The torsion bar applies a rotational resistance on the shaft which typically requires a certain amount of human input on the steering wheel to move the steering wheel from its current position in order to rotate the shaft and turn on the supplementary steering force. To this extent, once the rotational resistance is overcome by the human input and the shaft is slightly rotated, the supplementary steering force multiplies the human effort making it easier to turn the steering wheel. Generally, these systems measure the amount of torque applied by the human effort and provide correlational force. While these systems provide a significant improvement over steering configurations without power or assist systems, they still ultimately require a certain amount of human input for overcoming the initial rotational resistance of the torsion bar required to activate the supplemental force. This amount of required human input can vary drastically as a result of both the speed at which the automobile travels and the weight carried by the automobile. It is therefore desirable to add additional assistance to reduce or completely eliminate the human input required for overcoming sometimes inconsistent rotational resistances in order to initiate the supplementary steering force. Moreover, in applications where steering is autonomous and human effort is unneeded or unwanted, applications which bypass the human element are particularly advantageous. It is thus necessary to further advance the art which has traditionally required a certain amount of human input before application of supplementary steering force.